Preheat oven to 400F. Line a baking sheet with parchment paper.
Roll out the thawed puff pastry dough into a 10 inch by 12-inch rectangle (approximately). Make a half-inch border around the tart by folding the sides of the dough, using a fork to press down. Then use the fork to make dots throughout the middle of the tart and set aside.
In a bowl mix together all of the honey, melted butter, cinnamon, nutmeg, salt and flour. Then toss the sliced pears in the mixture.
Use a fork to remove the pear slices from the bowl and line up the pear slices on the puff pastry. Then, drizzle with up to 3 tablespoons of the remaining honey-butter mixture from the bowl. *If there is no remaining liquid simply move to the next step.*
Bake for 25-35 minutes or until the edges are dark golden brown.
Remove the oven and let cool on the baking sheet for 10-15 minutes. Sprinkle with walnut pieces before cutting and serving.